When to recheck serum sodium levels after infusion in patients with severe hyponatremia?

From the Guidelines

When sodium levels are critically low, recheck serum sodium levels every 2-4 hours during the initial correction phase with hypertonic saline infusion, then every 4-6 hours once stabilization begins, to prevent overly rapid correction and osmotic demyelination syndrome, as recommended for severe hyponatremia (<120 mEq/L) management 1. The goal rate of increase of serum sodium is 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period, especially in patients with cirrhosis, to ameliorate the risk of osmotic demyelination syndrome (ODS) 1. Some key points to consider when managing critically low sodium levels include:

• The use of hypertonic saline is reserved for short-term treatment of patients with symptomatic or severe hyponatremia 1
• The use of vasopressin receptor antagonists can raise serum sodium during treatment, but they should be used with caution only for a short term (≤30 days) 1
• Monitoring should include not only sodium levels but also neurological status, fluid balance, and other electrolytes
• If sodium rises too quickly, consider administering dextrose 5% in water (D5W) and possibly desmopressin 1-2 mcg IV to slow the correction
• Severe hyponatremia (<120 mEq/L) at the time of liver transplantation increases the risk of ODS, and multidisciplinary coordinated care may mitigate this risk 1

From the FDA Drug Label

Serum sodium concentrations were determined at 8 hours after study drug initiation and daily up to 72 hours, within which time titration was typically completed.

• Recheck sodium levels at the following intervals:
  • 8 hours after study drug initiation
  • Daily up to 72 hours
  • On Days 11,18,25, and 30 of treatment 2

From the Research

Rechecking Sodium Levels After Infusion

• The optimal timing for rechecking sodium levels after infusion is not explicitly stated in the provided studies, but it can be inferred based on the recommended correction rates and treatment targets.
• According to 3, a 4 to 6 mEq/L daily increase in serum Na concentration should be the goal in most patients, and inadvertent overcorrection can be avoided in high-risk patients with chronic hyponatremia by administration of desmopressin to prevent excessive urinary water losses.
• The study 4 recommends a treatment target of an increase in serum sodium by 5-10 mEq/L within the first 24 h and a maximum of 8 mEq/L during subsequent 24 h, suggesting that sodium levels should be rechecked at least every 24 hours.
• Additionally, 4 notes that overcorrection at 24 h occurred more frequently in patients with severe symptoms than with moderate symptoms, highlighting the importance of close monitoring in severely symptomatic patients.
• The use of hypertonic saline, as recommended in 3 and 4, requires careful monitoring of sodium levels to avoid overcorrection, which can lead to osmotic demyelination syndrome (ODS) 3.

Monitoring and Adjustment

• The provided studies emphasize the importance of monitoring sodium levels and adjusting treatment accordingly to avoid overcorrection and ensure a safe and effective correction of hyponatremia.
• The study 5 recommends a physiological approach to determine if hyponatremia is hypotonic, if it is mediated by arginine vasopressin, and if arginine vasopressin secretion is physiologically appropriate, which can help guide treatment and monitoring decisions.
• The use of desmopressin, as mentioned in 3 and 4, can help prevent excessive urinary water losses and reduce the risk of overcorrection in high-risk patients.